Method of registering finger-prints.



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EDWIN HEDBICK, 0F KENILVTORTH, ILLINOIS, ASSIG-NOR 'IO BAUDEB, IDENTIFICATION COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

METHOD OF REGISTERING FINGER-PRINTS.

No Drawing.

To all whom it may concern:

Be it known that I, EDWIN I-IEDRIOK, a citizen of the United States, residing at Kenilworth, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Methods of Registering F inger-Prints, of which the following is a specification.

Prior to my invention the method commonly employed for making records of finger prints is to take up on the ball of the finger, from a previously inked surface, sufficient ink to coat the ridges of the cuticle with a thin film of coloring matter, without permitting the ink to penetrate into the grooves or recesses between the ridges, and then, by applying the finger to paper or other object upon which the finger print record is to be kept, transfer the ink there to, thus leaving the imprint of the finger. This process is more or less successful, but is open to certain serious objections, among which may be mentioned that it smears the finger with pigment, which is objectionable from esthetic and sanitary considerations, and the linger print is further liable to smear not only at the time of making the same and while the ink is wet, but even thereafter when the print is exposed to moisture. It has also lately been proposed to reproduce the markings of the ball of the finger by pressing the same upon the paper or article upon which the print is to be recorded, and dusting over the invisible print formed by the thin film of natural oil on the finger an impalpable powder, comprising a pigment such as finely divided lamp black which adheres to the oily lines imprinted on the paper by the ridges of the cuticle, thus making the same plainly visible. Considerable difiiculty has been experienced in making impressions produced in this way permanent. It has been proposed to cover them with a coating of varnish, shellac or the like by means of a brush, but it has been found that the action of the latter tends to obliterate or smutch the print, and furthermore the coating so formed has a tendency to crumple the paper and render it brittle, both of which effects are decidedly objectionable in the particular uses to which this invention is to he put. A practice which has met with a. fair degree of success in this connection is to spray the print with a fixa- Specification of Letters Patent.

Application filed April 19, 1917.

Patented Nov. 2?, 191i?! Serial No. 163,287.

tive solution, but this process is open to the objection that a superfluous quantity of the solution is apt to be projected onto the print which requires to be blotted or otherwise absorbed, in which operation there is always a considerable risk of smearing the print. It is the purpose of my invention to provide a method of fixing the print which obviates all danger of interfering with the sharpness or definition thereof.

In the practice of my process the print is applied to the paper in the method last de scribed, to wit, by making an invisible imprint of the finger in the natural oil, or in case the finger is deficient in oil the lack may be supplied by pressing the finger upon a surface which is provided with a very thin film of an artificial oil. The print is made visible in the manner above described by brushing it over with a very finely divided pigment, thus producing as heretofore a distinct sharp reproduction of the lines of the finger tip which, however, without further treatment is liable to smutch. In order to make the record permanent I apply a wash of very dilute fixative to the reverse side of the paper over an area corresponding to that of the print, and the solution penetrates to the front of the paper causing the particles of pigment to adhere firmly thereto, thus rendering the print absolutely permanent. I have found a suitable solution for this purpose to consist in a dilute solution of about five per cent. shellac in alcohol or other solvent of shellac. Preferably a very volatile solvent is used in order that the paper may dry quickly. By applying the fixative in this manner the print is not exposed to the danger of smearing due to the application of the liquid to the face thereof whether by a brush or spray.

I claim:

A process for the production of permanent linger prints upon paper consisting in forming an imprint upon the paper by pressing on the surface of the paper the finger having a thin film of adhesive thereon, dusting a finely divided pigment on the print so formed, and fixing the print by applying to the reverse side thereof a penetrating fixing solution.

In testimony whereof I affix my signature.

EDWIN HE DRICK.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, a. t. 

